The present invention relates generally to encapsulated products containing edible active ingredients such as medicaments, foods and the like, and more particularly, to encapsulated products that offer improved security in combination with extended shelf life and physical integrity.
The products with which the present invention is concerned comprise encapsulated ingestible materials that have been in broad use and distribution for many years. Such encapsulated products have been prepared by the placement of flowable materials whether in powder or liquid form within the capsule structure which is generally prepared as two telescoping capsule halves. Accordingly, the contents of the encapsulated product are located within the capsule halves, and the capsule halves are then brought together into telescopic engagement and are thereafter sealed, whereupon the contents of the capsule are secured. Generally, such capsules are employed in the pharmaceutical and food industries and hold various edible and pharmaceutically active materials, such as medicines, vitamin preparations, and the like. The materials from which the capsule halves are prepared are usually hydrophilic, and are thereby adapted to dissolve in the intestines after ingestion. One of the prevalent difficulties and drawbacks to the use of capsules in the manner stated above has been their tendency to disengage and to prematurely release their contents. Accordingly, the prior art contains numerous disclosures directed to the establishment and maintenance of a sealing engagement between the capsule halves.
The problem of this engagement became more acute during the early part of this decade with the advent of the deliberate disengagement of encapsulated medicaments and the placement therein of certain poisons. Such deliberate activity was possible because of the inadequate sealing engagement between the capsule halves, and resulted in the decision by several of the major pharmaceutical firms to abandon the use of capsules as a dosage form for their medicaments. As a result, the pharmaceutical industry moved toward the use of a solid dosage form which externally resembled the capsule and which was known as the caplet. This dosage form, however, has met with limited consumer acceptance, and as a result, the manufacturers have now attempted to remedy this situation by the placement of a coating or capsule about the solid caplet, in an effort to improve the organoleptic properties of the dosage form.
A variety of techniques are therefore in use for the preparation of this composite solid dosage form, including the initial preparation of the caplet followed by the dipping, spraying or other application of an outer coating such as gelatin, and the friction-fit application of hollow capsules to the rigid caplets. Both of these approaches are time-intensive and frequently result in a product that is inadequate both commercially and for security reasons. The ability of the capsule halves to be dislodged from each other remains with the result that one can tamper with this solid dosage form and dispose a poison interstitially between the capsule half and its contents.
In addition to the shortcomings of the processes in use presently, Applicants have reviewed other literature relating to this subject and find no disclosures in the prior art respecting the products and corresponding processes of the present invention. For example, U.S. Pat. No. 3,432,592 to Speiser discloses the injection molding of an oral medicament in solid form, utilizing thermoplastic synthetic resins that are either insoluble or are of limited solubility, in large quantities for the purpose of developing delayed-release formulations. The resins used by Speiser include both polycondensation and polyaddition resins which are present in amounts of from 60% to 80% of the total tablet content. The temperature at which these materials are processed is substantially elevated and, for example, ranges upwards of 80.degree. C. to 160.degree. C. Such formulations, however, because of their limited solubility and composition are only useful in the instance where delay in release of the active ingredient is desired. Moreover, the elevated temperature at which the materials are processed would result in an undue amount of loss or attenuation of the active ingredients most commonly formulated by encapsulation, as the ingredients would either break down or would flash off at these temperatures. Accordingly, the disclosure of Speiser does not offer a solution to the problems faced in the capsule art as to the development of prompt release encapsulated materials offering desired organoleptic properties.
U.S. Pat. No. 4,082,024 to Moreland represents an alternative to conventional encapsulation wherein the contents of the capsule and the capsule material are co-extruded and then formed into capsule shapes. The Moreland disclosure relates primarily to the formation of an encapsulated product by the simultaneous disposition of the contents of the capsule and the capsule-forming materials in a continuous cylindrical mass which is then individually out and shaped to form the encapsulated product. Nothing in Moreland discloses the use of conventional preformed capsules or the preparation of a solid product including solidified capsule contents.
The remaining prior art comprising U.S. Pat. Nos. 4,673,438; 4,591,475; and 4,655,840 all relate to the manufacture of the capsule halves by injection molding techniques, including reference to appropriate capsule-forming compositions. Nothing in these disclosures relates to the formation of solid encapsulated dosage forms and therefore offers no suggestion to the artisan with respect to the problems faced and to appropriate solutions.
The need therefore exists for the development of a solid encapsulated dosage form offering the desired organoleptic properties of an encapsulated product in combination with the security and shelf stability afforded by a solid dosage form.
In co-pending application Ser. No. 07/272,734, the disclosure of which is incorporated herein by reference, a method for the preparation of an improved solid encapsulated product was disclosed. This product provides a solid encapsulated dosage form offering the desired organoleptic properties of an encapsulated product in combination with the security and shelf stability afforded by a solid dosage form. The present disclosure covers an alternate method for the preparation of the inventive dosage form that provides a product having all of the improved properties attainable in accordance with applicant's earlier disclosure.